{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{6}{c}}
\hline\hline
            &\multicolumn{1}{c}{Sh. Min. Wage}   &               &\multicolumn{1}{c}{Sh. Written Contract}   &               &\multicolumn{1}{c}{Sh. Social Security}   &               \\
            &\multicolumn{1}{c}{(1)}&\multicolumn{1}{c}{(2)}&\multicolumn{1}{c}{(3)}&\multicolumn{1}{c}{(4)}&\multicolumn{1}{c}{(5)}&\multicolumn{1}{c}{(6)}\\
            &\multicolumn{1}{c}{6 M.}&\multicolumn{1}{c}{18 M.}&\multicolumn{1}{c}{6 M.}&\multicolumn{1}{c}{18 M.}&\multicolumn{1}{c}{6 M.}&\multicolumn{1}{c}{18 M.}\\
\hline
assignment  &      0.0154   &     -0.0284   &     -0.0492   &      0.0154   &      0.0831** &     0.00748   \\
            &    (0.0304)   &    (0.0453)   &    (0.0321)   &    (0.0222)   &    (0.0377)   &    (0.0431)   \\
\hline
\(N\)       &         302   &         267   &         305   &         335   &         362   &         328   \\
Mean        &        0.18   &        0.18   &        0.11   &        0.11   &        0.12   &        0.12   \\
\hline\hline
\multicolumn{7}{l}{\footnotesize Standard errors in parentheses}\\
\multicolumn{7}{l}{\footnotesize * p<0.10, ** p<0.05, *** p<0.01}\\
\end{tabular}
}
